Projection apparatus



June 1946. R. PECHKRANZ I PROJECTION APPARATUS Filed 091;. 23, 1942 3Sheets-Sheet 2 2, PE OH KRANZ 3y 2 6% A1 ORNEN.

June 4, 1946. R. PECHKRANZ ,5

PROJECTION APPARATUS Filed Oct. 23, 1942 s Sheets-Sheet s.

iNvENTOK z. n: cHkRmvz" as MM ATTORA/Eth Patented June 4, 1946PROJECTION APPARATUS Rodolphe Pechkranz, Geneva, Switzerland ApplicationOctober '23, 1942, Serial No. 463,296 In Switzerland October 28, 1941 6Claims. 1

The present invention relates to a projection apparatus with controlledchanging of slides (operated mechanically, pneumatically orelectrically, from a distance if desired), characterised in that itcomprises means for receiving a rectilinear magazine containing acertain number (30, for example) of slides (this term covers eitherplates or films, the latter in a frame or between two assembled glassplates) arranged parallel one after another, means for moving thismagazine forwards step by step, means for extracting, at each half ofthe magazine, a slide from it and bringing it into projection position,and means for bringing this slide back to its original place in themagazine before the latter advances one step, the whole being disposedin such a way that, immediately after projection, the slides are allreplaced in the magazine in their initial order.

The annexed drawings show, as an example, one embodiment of theapparatus according to the invention:

Fig. 1 is a side view of it, supposing its bellshaped cover to besectioned.

Fig. 2 is a longitudinal section of one detail and Fig. 3 is across-section corresponding to Figlife 2.

Fig. 4 is a side view of the reverse side to that shown in Figure 1,supposing the bell-shaped cover to be lifted 011.

Fig. 5 is a horizontal section according to V-V of Figure 4.

Fig. 6 is a cross-section according to VIVI of Figure 5.

The apparatus shown comprises a rectangular base I, on which it stands,bearing four pillars 2 supporting two plates 3, 4 parallel with the baseI.

A detachable bell-shaped cover 5 can be slipped over the top, enclosingall the members borne by the base I and the plates 3 and 4, as canbeseen in Figure 1.

The base I carries an electric motor 6 driving a propeller 1 serving asfan and a worm-screw 9, serving to drive at reduced speed a camshaft 9supported in its turn by two bearings Ill also fixed to the base I(Figures 1 and 6). An electro-magnet H and an electro-magnet I2 (Figures1 and 4) are also fixed to this base, the first serving to engage thecoupling and the second to disengage the coupling of the camshaft.

The plate I bears, fixed on it, slide-bars l9 between which arectilinear magazine runs longitudinally, containing a certain number(30, for example) of lantern slides arranged parallel one after another.By lantern slides is understood either plates or films, the latterplaced in a frame or between two assembled glass plates. The magazine I4can be inserted into or taken out of the apparatus without its beingnecessary to lift off the cover 5, thanks to a slit Ia on the frontside.

This plate 9 also bears other parts and various bearings that aredescribed farther on.

The plate 4 carries a sash-frame ii in which are incorporated the slidesin course of projection, the set of lenses iii, the lamp i1 and thetransformer i8.

On the shaft 9 is free-mounted a couplingsleeve I9 integral with ahelicoidal wheel 20 cooperating with the worm-screw 8. The edge of thesleeve i9 is toothed so as to mesh with similar teeth on a slidingcoupling-sleeve 2| on the shaft 9, but angularly integral with thelatter. The sleeve 2| is controlled in such a way that its teeth areeither engaged or disengaged with those on the sleeve 19. It is seen,then, that the teeth on the coupling-sleeves i9 and ii form a gearallowing of the transmission of the movement of the helicoidal wheel tothe shaft 9 when they are engaged. The shaft 9 bears, locked on it, acam 22 operating a shutter 23 that intercepts the light-beam from theprojection lamp ll during the operation of changing one slide foranother. This shutter, of course, occupies a position that leaves freepassage to the light-beam through the set of lenses when a slide is inthe projection position. Another cam 24 is also locked on the shaft 9and this operates the extraction one by one of the slides from themagazine l4, their individual bringing into position for projection andtheir return into the megazine after projection.

The shaft 9 also bears an electric contact drum 25, the contacts ofwhich are closed at certain given angular positions of the shaft. Therole of these contacts will be explained farther on. Finally, the shaft9 bears two cams 26, 21, the first of which operates the advance step bystep of the magazine, so asto ensure the projection of a slide after thepreceding one has been automatically returned to the magazine, and thesecond of which operates a locking and feeling device, serving toimmobilize the magazine during the projection and to determine atthe'same time if there is still in the magazine another slide to projectimmediately after that in the position of projection.

The different mechanisms driven by the cams just mentioned aresuccessively described below.

Device for operating the shutter 23 This device comprises a lever 22pivoted at one or its ends on a support 22 iixed tothe base I. Thislever 22 bears, fixed between its two ends, a roller 22 constantly heldagainst the cam 22. A vertical rod 2|, sliding in guides in the plates 2and l, is pivoted at its lower end on the lever 22, near the oppositeend to that pivoting on support 22. The rod 2| is constantly pulledupwards by a spring 22 wound round it in the space between the plates 2and 4. It is this spring that holds in place the roller 20 pressedagainst the cam 22. At its upper end, the rod 2i bears a horizontal bar22 fixed to the former atone of its ends; the free end of this bar 22 isguided by a fixed fork 22. The horizontal bar 22 bears the shutter 22through the intermediary or a short lever 25. It is easily seen that,according to at what distance the roller is from the shaft 9i. e.,according to on which part of the cam it is ridingthe.shutter is foundeither in the position shown in the drawing where it intercepts thelight-beam intended for the objective or lowered below this position outof the course of the light-beam.

The free end 01' the lever 28 bears a stop 26 which strikes against alever 21, fixed on a shaft 2% angularly integral with a throw-out fork29 controlling the coupling-sleeve 2! oi the gearing. Whenthe stop 22strikes the lever 37, following on the lowering of the shutter throughthe effect of the cam 22, the shaft 32 is bound to revolve clockwise onFigure 6, which brings about the disengagement oi the coupling-sleevesi9 and 2|. This happenawhen the shutter 28 arrives at its lowestposition.

Device controlling the slides This device serves to extract the slidesone by one from the magazine H, to bring forward each slide so extractedto the projection position, then to return it to the magazine and toextract the next slide and so on, in such a way that there is never morethan one slide at a time out oi the magazine. This device comprisesalever 40 pivoting at one of its ends on a support it fixed to the baseI. This lever bears, between its two ends, a roller 42 kept constantlypressed on the cam 24 by a spring 43 hooked to the plate 3. A crutch itjoins the lever 40 to another rocking-lever 45, pivoted at one of itsends on a support 46 borne by the plate 3. The other end of the'lever Iis pivoted on a connecting-rod ll, acting on a horizontal bar 48, to oneend of which is fixed a vertical rod 49 guided by the plates 2 and l andbearing at its upper end an elbow-piece it intended to act on the slideso as to help it to descend again into the magazine.

The horizontal bar 48, bears, at its other end, a

vertical rod 5| acting. from below on the slide to be brought into theprojection position, by lifting it and making it run between the guidesit. When the roller 42 draws near the shaft 9 by riding the cam 24, therod 5| ascends, yielding to the action of the spring 43, and a slide isbrought into the projection position. When, on the contrary, the cam 24drives the roller away from the shaft 9, the elbow-piece 50 forces theslide, locked in the guides ii, to return to its place in the magazine.

Device for advancing the magazine step by step This device comprises alever 52 pivoted, close to enact its ends, on a support 52 fixed to theplate 2. This, lever bears, at its other end, a

asossoe 4 roller it constantly held against the cam 22 by a spring llhooked to the plate 2. The upper end of the lever '2 drives backwardsand forwards a carriage I8 (seen in Figures 4, 5 and 6). This carriagebears a forwarding pawl 51 cooperating with a rack 50 cut-on one of thelateral sides of the magazine. The width of each tooth of this rack 58measured at the basis of the tooth is equal to the distance between thecenter planes of two adjacent slides. Thus, one revolution of the cam 22causes the magazine to advance by the action of forwarding pawl 21entering into the space between two teeth of the rack to the extent ofthe width of one tooth which is equal to the distance between twoslides: simultaneously the pawl 51 is returned into its initial positionby carriage 58. a

Locking and feeling device This device comprises a lever 52, pivotingbetween its two ends on a support 82 fixed to the base i and pulled by aspring 8i hooked at 22 to the base I. This lever bears, at one of itsends, a roller 62, constantly held against the cam 21 by the spring 6|.To the other end of the lever 59 is pivoted the lower end of a verticalrod 64 guided through the plates 2 andl and bearing, in the spacebetween these two plates, a member 65 provided with an inclined plane 68forming a wedge (Figure 6). When the member 65 descends, the inclinedplane 68 immobilises a ratchet 61 placed above the pawl 51and'co-operating also with the rack is. The role of this ratchet 61 isto keep the magazine stationary during the return movement 01" the pawl57 which, in the absence of the ratchet 81, would tend to bring themagazine back with it The rod 66 bears, at its upper end, a feeler 68which serves to determine if there is, in the magazine, a slidefollowing that at the moment in projection position. The operation thatthis feeler controls are described below.

Automatic return of the magazine under the control of the feeler 68 Whenthe magazine I l is inserted in the apparatus, it freely runs along theslide-bars l2 up to the point where a pin 69 (Figure 6) engages in alittle notch 10 on the side of this magazine. From that moment, themagazine cannot advance without a tendency to move backwards, for thispin 69, fixed to a lug ll integral with a shock-absorbing piston slidingin a pneumatic tube 12 (Figures 1 and 6) is pulled backwards by a cableI2, winding in a groove of a springbox 14 containing a return-spring notshown in the drawings. Normally, however, the magazine cannot movebackwards, for it is arrested, at the moment of its advance, by the pawlI51 and,

'when the pawl has ceased its action, by the ratchet 61, itself keptengaged with the rack 58 by the inclined plane 28.

So that the magazine may obey the pull of the spring in the spring-box14, and move backwards, the pawl 51 and the ratchet 21 must besimultaneously disengaged from the rack. Due to stop I22 provided at theside of ratchet 21 adjacent to the magazine and slightly projectingdownward therefrom over pawl 51 the ratchet when rotated about pivot .INby lug 22, as described later on, takes along pawl 51; therefore, thedisengagement-of the ratchet involves that of the pawl. The release ofthe magazine-i. e.,

its disengagement from the ratchet of the rack- I i .5 can be broughtabout in two ways: by hand or automatically.

Release of the magazine by hand The ratchet 61 must be disengaged fromthe rack when-it is desired to take the magazine out of the apparatus.This is done through the following parts:

A knob I appearing on the front face of the apparatus (Figures 1 and 5)allows of the turning of a bar a bearing a cylindrical cam I8 (Figure1). When the knob I5 is turned, the cam 18, turning with it, rocks alever TI on a pivot "I8 (Figure 5). The other end of this lever" 11pushes towards the front of the apparatus (so towards the right onFigure 5) a bar I9 acting on a lug 88 integral with the ratchet 81 (Fig.5). The ratchet is thereby rotated about pivot 8| and its tip iswithdrawn from the rack 58 of the magazine. As the ratchet brings thepawl with it, as has been described above, the magazine is no longerheld back by these two members. The bar 15a bears -a longitudinal boss82 (Figure 6) which sepa- Extraction of the magazine from the apparatusand checking of the number of the slide proiected A knob 83, in linewith the knob I5 in relation to the median longitudinal plane of theapparatus (Figures 4 and 5) allows of drawing out from the apparatus ascaled square bar 84 lengthened at the back by a round bar 85 joined toa parallel round bar 86 by a bridge 81. The free end of the bar 88pushes the magazine towards the front (i e., to the right on Figure 5).When the knob 83 is pulled, the magazine resists if the latter is heldback by the locked ratchet 61. In the first case, the magazine is pushedout of the apparatus up to a point where it is possible to seize it withthe hand; in the second case, the scaled rule projects from theapparatus to an extent that depends on the serial number of the slidewhich is in the projection position. The graduations of this rule arescaled in such a way as to indicate at once the serial number of theslide.

described above, is to allow the magazine to be drawn back by the springin the spring-box I4 in the case of the automatic functioning of theapparatus.

The helicoidal wheel 28 is integral with a cam 88 (Figure 2). Once inevery revolution, this cam raises a rocking-lever 89 bearer of a roller98. This lever is itself borne by a shaft 9I turning in the bearings 92,93 (Figures 2 and 4. This shaft is integral with a crank" 94, raisingand lowering a connecting-rod 95 at each revolution of the-shaft 9. Thisconnecting-rod is pivoted on another crank 96 borne by a short shaft 91(Figure 5), revolving in the bearings 98, 99. The shaft 91 bears acrankI88, only partially seen as a dotted line in Figure 4, behind thebearing 99. To this crank is pivoted a pusher I8I running'in a ring I82integral with a beam I83 pivoting at I84 on a support I85 integral withplate 8. This pusher I8I' is, therefore, motivated at each revolution ofthe helicoidal wheel to effect a horizontal to-and-fro movement. The endI86 touch the lug 88 oi the ratchet 81, because it passes underneath it.

If the feeler 88 does not encounter a slide in the slot of the magazineimmediately following that of the slide projected, rod 84 .will at themoment when the cam 21' allows of this movement, further descend and aprojection I 8'! at, tached to part 85 will impact lever I88 and causeit to rotate about pivot I84. The left hand end (see Fig. 5) ofthe leverI88, which bears a dog I88, rises and takes up with it the ring I82.Because 01' that, the pusher I8I now directs its tip I86 against the lug88 of the ratchet 8'! and, by its to-and-fro movement, disengages theratchet, and with it, as was seen above, the catch, from the magazine.The magazine can then yield to the pull of the spring in the spring-boxI4 and return right to the back of the apparatus to its point ofdeparture. At the end of its run, the magazine I4 meets a stop I89integral with a horizontal rod II8 supported by a crank II I and whichcan slide for a few millimeters in a pillar II2 fixed to the plates 3and 4. A crank member II3 (seen only as a dotted line in Figure 4)acting on the end of the lug 88 of the ratchet 61, pivoting at H4 and onwhich the rod II8 acts, causes the pivoting and the release of theratchet 61 and the pawl 51, which stopped in the open position. The dogI88 of the beam I83 has also been disengaged. The ring I82 has descendedand the pusher I8I is rendered inactive, for it begins again to passunderneath the lug 88 of the ratchet 81.

Electrical coupling and uncoupling The apparatus is planned to operatethe changing of slides by itself when the user, a lecturer for example,closes an electric circuit by a switch not shown and which could verywell be at a long distance from the apparatus. The couplingelectromagnet II (Figure 1), when it is energised by the closing of thecircuit in question, acts on an armature not shown fixed to the shaft38, making this shaft revolve anti-clockwise on Figure 6, which, thanksto the throw-out fork, couples the teeth of the sleeves I9 and 2I of thegearing.

The uncoupling then automatically takes place after one revolution ofthe camshaft, when a fresh slide is in projection and that is due to thestop 36, which acts on the lever 31 fixed to the shaft 38, making thatshaft revolve clockwise on Figure 6.

When the last slide in the magazine has been projected and has returnedto the magazine, the camshaft must stop in the position shown in thedrawings. Now, at that moment, the pusher is at the top of its stroke,since the shutter is closed-- i. e., it intercepts the light-beam. Anelectrical uncoupling has therefore to be provided for. The circuit ofthe uncoupling electromagnet I2 is closed by a cut-out not shown,constituted by a contact co-operating with the contact cylinder 25. Theuncoupling electro-magnet I2, Figure 4, acts on an armature (not shown)fixed to the shaft 38, making that shaft revolve clockwise on Figure 6,and that, through the intermediary of the throw-out fork 39 (Figure 6),separates the two sets of teeth on thesleeves I9, 2 I

Counting device If'the apparatus has to function 'automaticallyforexample, if it is to be used for publicity purposes-the counting devicethat is now to be described intermittently and automatically works 7 thecoupling each time an adjustable specified interval has assed. Thisinterval is counted by the device as a number of revolutions of thecamshaft.

The cam ll, integi' lwith the helicoldal wheel 20, the same one thatreleases the magazine, acts once every revolution on a bent to le-leverIII, pivoting at I It on a support iII fixed to the base I. One of thearms of this lever bears, in fact, a roller H8 riding on this cam, whileits other arm bears a bowl 0, pulled, by a spring I20, to cooperate witha vertical rack I. This pawl, at each revolution of thecam ll, lowersthe rack I2I one pitch and the rack is held in this new position by aratchet I22, while the pawl H returns to its original position. Whenthis rack has descended far enough, the head of a screw I23 fixed on itswings the branch of the lever 31 opposed to that on which the stop 2!acts, as was seen above. This movement of the lever 31 rocks the shaft30 anticlockwise on Figure 6 and that ensures the co-operation of thesleeves I0, 2i of the coupling-gear through the intermediary of the fork30. The store-mentioned movement of the lever 31 has also for effect tolower a counterrod I24 which, by means of two pins I25, I25, acts on ahorizontal branch of the pawl III and the ratchet I22 so as to separatethem from the rack. This rack, constantly pulled upwards by a springI26, returns to the upper position and is thus ready to be moved pitchby pitch downwards again by the pawl. The camshaft has started revolvingand, 360 later, the stop II of the lever 20 belonging to the deviceworking the shutter causes the-uncoupling by rocking the lever 31.

The counter-rod I24 can in its turn ascend again through the eifectof aspring I21.

Regulating the time of the projection The manner of regulating the timeinterval during which the projection takes place under the control ofthe counting device just described is as follows:

When the rack I2I ascends, a boss I20 that it bears strikes against aninclined plane I20, Figure 2. This inclined plane occupies an adjustable1 position. In Figure 2 it is shown in its extreme position to theright. If it is moved towards the left (on Figure 2) by the intermediaryof parts Ill, iii and held in its new position by means of a milled nutI32, the rack ascends less high than before and consequently it hasfewer pitches to pass to arrive at the bottom position. 80, changing theposition of the inclined plane I2! by means of the nut I22, the numberof revolutions is Semi-automatic working of the apparatus The inclinedplane in is brought to its extreme left position on Figure 2. By meansof a switch not shown, the lamp is lit and the motor started. Thecamshaft 0 is in the position shown in the drawings, to be called thezero degree position. Pressure on an electric push-button starts thecamshaft by means of the electro-magnet II. The locking of the ratchetof the magazine first takes place, then a slide ascends to the rojectiontreme-left position of the inclined plan counting device is working.After the rack has 8 position, the shutter 22 comes away from thelight-beam and, at the end of its course, causes the uncouplin of theteethof the sleeves II, 2i. The camshaft is at from its point ofdeparture. It stops, while the motor, the'wormscrew, the helicoidalwheel and the cam 8| continue to revolve.

c ntin device and also the feeler are neutralised. The lamp, the lensesand the slide which is in projection position are cooled by the aircoming from the fan 'I and directed along suitable air-shafts of whichone can be seen at I. Nothing happens till the user presses the controlbutton, energising afresh the coupling electromagnet. The camshaftstarts revolving, the shutter closes. the slide descends, the magazineadvances one pitch, the ratchet of the magazine is locked, a fresh slideascends into the projection position, the shutter opens and causes theuncoupling. We are again at 180.

This cycle is renewed with each pressure on the control button until allthe slides have passed or until action on a main switch has extinguishedthe lamp and electrically set the camshaft in motion. Then the shuttercloses. the slide descends into the magazine. which advances one pitch,but the contact cylinder 25 operates the final uncoupling in the zeroposition of the camshaft. Finally, the motor, to which current has beenfurnished by the contact cylinder despite the interruption of thegeneral switch, stops because the current from the drum is cut oil!several degrees before zero position.

Automatic working of the apparatus The inclined plane I2! is elsewherethan in its extreme-left position on Figure 2. The departure is the sameas for semi-automatic working up to the 180 position of the camshaft.The push-button has no action, its circuit is closed by a contact whichis neutralised only for this ex- I2l; the

progressed downwards for a specified number of itches, it mechanicallyoperates the coupling: the camshaft then makes a complete revolution andreturns to 180, effecting all the operations described in the precedingparagraph. At the re-opening of the shutter, the uncoupling isautomatically eifected and the counter begins workin again.

If the feeler, which is feeling while the slide in projection isreturning to its place, meets with no resistance-that is, if the nextslot of the magazine is emptyit causes the switch-over of the pusher IIIwhich separates the pawl and the ratchet from the magazine. Themagazine, pulled backwards, strikes a stop which causes the pawl and theratchet to go back into place, and, furthermore, occasions a freshelectrical coupling and the whole cycle recommences, the successiveslides being again projected in their turn.

Cooling device 7 The cam has no action, for, v v in this position of theinclined plane I20, the

air-duct m against one side of the slide in propendicularly passingthrough the magazine It owing to the opening I38 in the bottom of thismagazine and through the gaps between the different slides that itcontains. The air-current through this magazine is particularly intensein the space left empty by 'the'slide actually in the projectionposition. In this way, the slide is cooled on its two sides and run norisk ofbeing injured by an increased temperature due to the powerfulradiance of the lamp IT.

The lamp I1 is preferably provided with a bayonet-holder fixed in asocket I89 placed in such a way that there is, between the'neck of thelamp and the inside of the socket a ringed space through which a streamof air flows upwards under the influence of the fan. This stream of aircompletely encircles the neck and body of the lamp. Owing to itscirculation in a direction parallel with the axis of the lamp, the airkeeps the neck of the lamp at a low temperature.

What I claim is:

l. A projection apparatus comprising a rectilinear magazine containing aplurality of slides in parallel adjacent relationship, a shutter, a mainshaft, a motor to drive said shaft, 9, coupling on said shaft todrivingly connect the same with said motor and to disconnect the same, acam on said main shaft, a roller carrying rod and lever system actuatedby cooperation of said roller with said cam to lift during eachrevolution of the latter one slide from said magazine into theprojecting position and to return the slide after projection into saidmagazine, a second cam on said main shaft, a roller carrying lever tohereciprocated by cooperation of said roller with said cam, a magazineforwarding pawl connected with said reciprocating lever, a toothed rackadapted to be displaced by said forwarding pawl attached to saidmagazine, the width of each tooth corresponding to the distance betweentwo slides, whereby the magazine is moved during each revolution of saidcam at the extent of one tooth equal to the distance between two slides,a third cam on said main shaft, a roller carrying rod and lever systemactuated by cooperation of said roller with said cam to lift during eachrevolution of the latter said shutter into the obturating positionduring the lowering of the slides into the magazine and to lower theshutter out of the obturating position during the lifting of the slidesinto the projecting position, a fourth cam on said main shaft, a rollercarrying lever and rod system actuated by cooperation of said rollerwith said cam to lift and to lower said rod, an inclined plane carryingmember attached to said vertical rod to immobilize upon descent of saidrod the magazine by said inclined plane member at each revolution of thecam during the lifting from and the return of the slides into themagazine.

2. A projection apparatus comprising a rectilinear magazine containing aplurality of slides in parallel adjacent relationship, a shutter, a

, main shaft, a motorto drive said shaft, a coupling on said shaft todrivingly connect the some cases ver to be 'reciprocated by cooperationof said roller with said cam, a magazine forwardin pawl connected withsaid reciprocating lever, a

toothed rack adapted to be displaced by said for-- warding pawl attachedto said magazine, the width of each tooth corresponding to the distancebetween two slides, whereby the magazine is moved during each revolutionof said cam at the extent of one tooth equal tothe distance between twoslides, a third cam on said main shaft, a

roller carrying rod and lever system actuated by with said motor and todisconnect the same, a

cam on said main shaft, a roller carrying rod and lever system actuatedb cooperation of said roller with said cam to lift during eachrevolution of the latter one slide from said magazine into theprojecting position and to return the slide after projection into saidmagazine, a second cam on said main shaft, a roller carryinglecooperation of said roller with said cam to lift during eachrevolution of the latter said shutter into the obturatingpositionsduring the lowering of the slides into the magazine and tolower the shutter out of the obturating position during the lifting ofthe slides into the projectin position, a fourth cam on said, mainshaft, a roller carrying lever and rod system actuated by cooperation ofsaid roller with said cam to lift and to lower said rod, an inclinedplane carrying member attached to said vertical rod to immobilize upondescent of said rod the magazine by said inclined plane member at eachrevolution of the cam during the lifting from and the return-of theslides into the magazine, an angular feeler attached to the upper end ofsaid vertical rod to project into the magazine and to determine thepresence of a slide following the one in the projecting position.

3. A projection apparatus comprising a rectilinear magazine containing aplurality of slides in parallel adjacent relationship, a shutter, a

main shaft, a motor to drive said shaft, a ecu-- projection into saidmagazine, a second cam on said main shaft, a roller carrying lever to bereciprocated by cooperation of said roller with said cam, a magazineforwarding pawl connected with said reciprocating lever, a, toothed rackadapted to be displaced by said forwarding pawl attached to saidmagazine, the width of each tooth. corresponding to the distance betweentwo slides.

whereby the magazine is moved during each revolution of said cam at theextent of one tooth equal to the distance between two slides, a thirdcam on said main shaft, a roller carrying rod and lever system actuatedby cooperation of said roller with said cam to lift during eachrevolution of the latter said shutter into the obturatins positionduring the lowering of the slides into the magazine and to lower theshutter out of the obturating position during the lifting of the slidesinto the projecting position, a fourth cam on said main shaft a rollercarrying lever and rod system actuated by cooperation of said rollerwith said cam to lift and to lower said rod, an inclined plane carryingmember attached to said vertical rod to immobilize upon descent of saidrod the magazine by said inclined plane member at each revolution of thecam during the lifting from and the return of the slides into themagazine, an angular feeler attached to the upper end of said verticalrod to project into the magazine and to determine the .presence of aslide following the one in the projecting position, a projection carriedby said rod to terminate upon further descent of said rod due to absenceof a slide the immobilisation of said magazine,

11 a and means to return the now freely movable magazine. into itsinitial Position.

' 4. An automatic continuously operable slide projector comprising incombination a frame. a rectangular slide magazine located in said frame,a plurality of slides arranged in parallel adjacent relationship in saidmagazine. a shutter, a magazine locking and slide presence determiningdevice, a motor underneath said magazine, and a main shaft driven bysaid motor. a coupling on said shaft to drivingly connect the same andthe motor and to disconnect the latter, a cam on said shaft. meansoperated by said cam to advance said magazine for the distance oi twoadjacent slides, said means including-a roller carrying lever to bereciprocated by cooperationof said rollerwith said cam. a spring to keepsaid roller in permanent contact with said cam, a carriage to bedisplaced by said lever, a magazine forwarding pawl carried by saidcarriage, a toothed rack adapted to be displaced by said forwardingpawl, said rack being attached to said magazine, the width of each toothcorresponding to the distance between 12 slide is lifted into theprojection position. said means includinga lever supported movableroller. a spring to keep said roller in permanent contact with saidearn, a lever and rod arrangementconnected with said shutter to move thesame upward into the obturating and downward into the nonobturatingposition. a stop carried by said roller supporting lever, means actuatedby said stop-to disengage said motor coupling when the shutter is in itslowest position. a fourth cam on the same shaft, means operated by saidcam to arrest the magazine during the projection and to determine thepresence of unused slides, said means with said com, a rod and leverarrangement operated by said roller carrying lever to actuate a magazinelocking ratchet, and a feeler actuated-bysaidrodtoprojectintosaidmagazineandto two slides, whereby saidmagazine is moved during each revolution of said cam for the'distance oftwo slides, a second camon the same shaft. means operated by said secondcam to extract the slides one by one from the magazine to move the sameinto the projection position and to return them after projection to themagazine before the magazine can be-advanced, said means including alever supported movable roller, a spring to keep said roller inpermanent contact with said cam, a leverage system controlled by saidroller to lift the slides, and guides to receive the slides to lead thesame into the projection position and to return them into the magazine.a third cam on the same shaft. means operated by said third cam to movesaid shutter into the obturating position.

while aslide is returned into the magazine. and

determine if there is a slide in the magazine following that inprojecting position.

5. In an automatic continuously operable slide projector according toclaim 4, means operated a by the ieeler upon determination of theabsence into the magazine including a vertically movable horiaontal bar.carrying at its one end a vertical shorter rod to lift the slides duringthe ascent of said bar into the projecting position and carrying at itsother end a vertical longer rod terminating into an elbow. piece to pushthe slides duringthedescentofsaidbarintothemagazine.

RODOLPHI Pncmmsnz.

